Wieghardt et al., in J. Am. Chem. Soc., 110, 7398 (1988) describe the synthesis of [MnIV2(μ-O)3(Me3-TACN)2](PF6)2 (Me3-TACN=1,4,7-trimethyl-1,4,7-triazacyclononane) as solid materials by precipitation of the compounds containing the large non-coordinating PF6 counterion. The [MnIV2(μ-O)3(Me3-TACN)2](PF6)2 is prepared by reacting a dinuclear bis-carboxylate bridged Me3-TACN manganese (III) complex in ethanol/water mixture and air (dioxygen).
Wieghardt et al., in J. Am. Chem. Soc, 120, 13104 (1998) describe the synthesis of [MnIVMnIII(μ-O)2(μ-OAc)(Me4-DTNE)](ClO4)2 and [MnIVMnIII(μ-O)2(μ-OAc)(Me4-DTNE)](BPh4)2 (Me4-DTNE=1,2-bis-(4,7-dimethyl-1,4,7-triazacyclonon-1-yl)-ethane and BPh4 is tetraphenylborate) as solid materials by precipitation of the compounds containing large non-coordinating counterions. The [MnIVMnIII(μ-O)2(μ-OAc)(Me4-DTNE)](ClO4)2 is prepared by reacting Mn(III) acetate in methanol and allowing slow aerial oxidation to form the complex.
Koek et al., in Inorg. Chim. Acta, 295, 189 (1999) describe the synthesis of dinuclear Mn(IV) complexes based on TACN derivatives as hexafluorophosphate salts using water/ethanol mixtures.
WO 96/06154 describes the synthesis of [MnIVMnIII(μ-O)2(μ-OAc)(Me4-DTNE)](PF6)2 by reacting Mn(II) acetate tetrahydrate in ethanol/water in the presence of KPF6, after which hydrogen peroxide/NaOH was added and subsequently neutralised using acetic acid.
WO 2006/125517 discloses the preparation in aqueous media and use of manganese complexes with Me3-TACN and Me4-DTNE as highly water-soluble salts in bleaching. The complexes were prepared in situ and were not isolated as solid materials.
U.S. Pat. No. 5,274,147, to Unilever, discloses the formation of tri-μ-oxo bridged manganese complexes containing Me3-TACN carried by treatment of dinuclear bis-carboxylate bridged complexes in aqueous ethanol solutions, to yield PF6 or perchlorate salt complexes.
U.S. Pat. No. 5,153,161, to Unilever, discloses the formation of tri-μ-oxo bridged manganese complexes as PF6 salts containing Me3-TACN obtained by treatment of aqueous solutions of ligand with manganese salts and hydrogen peroxide.
U.S. Pat. No. 5,256,779, to Unilever, discloses the formation of tri-μ-oxo bridged manganese complexes containing Me3-TACN obtained by treatment of aqueous solutions of ligand with manganese salts and hydrogen peroxide.
WO 2011/032666, to Clariant, describes the synthesis of dinuclear manganese and iron complexes containing Me3-TACN or Me4-DTNE as PF6, perchlorate or tetraphenylborate salts by using only water in the synthetic procedures.
WO 2011/066934 and WO2011/066935, both to Clariant, describe the synthesis of dinuclear manganese complexes containing Me3-TACN or Me4-DTNE as tosylate salts, yielding non-hygroscopic solid complexes.
Manganese ion-containing complexes, typically dinuclear manganese ion-containing complexes, comprising MnIII and/or MnIV ions and ligands based upon triazacyclononane (e.g. Me3-TACN), are typically formed by allowing manganese salts (often MnII salts) to react with the triazacyclononane-based ligand in aqueous solvents under inert conditions (e.g. nitrogen or argon atmosphere), after which hydrogen peroxide is usually added to form catalytically active high-valent MnIII and/or MnIV species.
Isolation of salts of manganese complexes comprising, for example, Me3-TACN or Me4-DTNE ligands, and which are poorly water-soluble, such as the PF6, ClO4, tetraphenylborate and tosylate salts, from aqueous solution is straightforward, as is shown in the prior art. However, the isolation of salts of complexes comprising non-coordinating ions that make the complexes highly water-soluble, for example chloride, acetate, benzoate, sulfate or nitrate, is problematic: it is difficult to remove the water without causing decomposition of the complexes when performed under reduced pressure or at higher temperatures.